[wmoser]

They are also used quite a lot in building trades or wood working or machining. Pitch of roofs are often given as a ratio, tapers on machinery shafts, making sure your pipes have sufficient slope to drain properly. Another construction example would be how long of a board do you need for the stringers (the long boards that are notched for the stairs if it has to go up 10ft over a fifteen foot distance, etc. whether they might end up the designer or the constructor of things it's probably one of the more practical math concepts.

[joeclark77]

And add to that that the 3-4-5 triangle is still a useful way to establish a right angle without any tools (apart from a piece of string).